Persistent Disk (GCP)
The block storage attached to a Compute Engine VM, equivalent to an AWS EBS volume or Azure Managed Disk. Persistent Disks come in zonal (replicated within one zone, lower cost) and regional (synchronously replicated across two zones, survives a single zone failure) variants.
Frequently Asked Questions
What's the difference between zonal and regional Persistent Disk?
Zonal Persistent Disk lives in a single zone and is cheaper — if that zone fails, the disk is unavailable until the zone recovers. Regional Persistent Disk synchronously replicates writes to a second zone in the same region, so a VM can fail over and remount the disk elsewhere with no data loss. Regional PD costs roughly double zonal PD and adds a small write-latency penalty from the cross-zone replication acknowledgment.
Can I resize a Persistent Disk without downtime?
Yes — you can grow a Persistent Disk live while it's attached and in use, no reboot needed. The catch is that GCP only lets you increase size, never shrink it, and growing the disk doesn't automatically extend the filesystem; you still have to run resize2fs, xfs_growfs, or the Windows equivalent inside the guest OS. A common mistake is resizing the disk in the console and then wondering why `df -h` still shows the old size.